关于delphi：向事件运行时添加函数

Add function to event runtime

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

procedure TFormOrderAdd.DBEdit1DblClick(Sender: TObject);
var
FormSelectEmp: TForm;
SelectEmpDBGrid: TDBGrid;

begin
FormSelectEmp := TForm.Create(Self);
SelectEmpDBGrid := TDBGrid.Create(Self);
SelectEmpDBGrid.Parent := FormSelectEmp;
SelectEmpDBGrid.Align := alClient;
SelectEmpDBGrid.DataSource := DMl.DataSourceViewEmpList;
FormSelectEmp.ShowModal;
SelectEmpDBGrid.OnDblClick := AddSelectedEmp;
FormSelectEmp.Close;
end;

procedure TFormOrderAdd.AddSelectedEmp;
begin
DBEdit1.Text := Dml.ADOQueryViewEmpList.FieldByName('ID').Text;
end;

如何将我的程序添加到 OnDblClick 事件？
我尝试分配，但编译器说：[dcc32 Error] OrderAdd.pas(66): E2010 Incompatible types: 'TNotifyEvent' and 'procedure, untyped pointer or untyped parameter'

相关讨论

您必须在一个类中创建一个匹配的事件方法原型，然后将其分配给事件处理程序(对于 TDBGrid 控件的 OnDblClick 事件，它是 TNotifyEvent)，因此您可以编写例如：

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26

type
TForm1 = class(TForm)
DBEdit1: TDBEdit;
DBGrid1: TDBGrid;
private
procedure Form1Create(Sender: TObject);
procedure MyGridDblClick(Sender: TObject);
end;

implementation

procedure TForm1.Form1Create(Sender: TObject);
begin
{ it doesn't matter if you create the component at runtime,
this is a common principle of assigning event methods at
runtime - they just have to match the method prototypes }
DBGrid1.OnDblClick := MyGridDblClick;
end;

procedure TForm1.MyGridDblClick(Sender: TObject);
begin
{ to access the grid instance in case more than one grid
uses this handler you can use TDBGrid(Sender) or safer
cast (Sender as TDBGrid) }
DBEdit1.Text := TDBGrid(Sender).DataSource.Dataset.FieldByName('ID').Text;
end;